Projecting microscope and viewing device



July 26, 1949.A E. c. wExsKoPF 2,477,395

PROJECTING MICROSCOPE AND VIEWING DEVICE Filed Aug. 27,1946 1osheets-sheet 1 INVENTOR EDWIN C. WEISKOPF ATTORNEY cnn NE o5 :n En n N mEn 2N im Nn nvm 8N N9 ,VN o m\ U No www v u bm VIII IL 3N own mm 2m omEn Y .1 N* A\w 2 I 8 /M ,X l 4 tr N. m\\ @n y u1 mv vn am n QN July 26,1949. E.v c. wr-:lsKoPF PROJECTING MICROSCOPE AND VIEWING DEVICE osneets-sheet 2 .Filed Aug. 27, 1946 INVENTOR EDWIN C. WEISKDPF BYl CATTORNEY July 26, 1949. E. c. wElsKoPF 2,477,396

PROJECTING MICROSCOPE AND VIEWING DEVICE Filed Aug. 27, 1946 lOSheets-Sheet 3 www@ INVENTOR EDWIN C. WEISKOPF ATTORNEY July .26, 1949.E. c. wElSKoPF PROJECTING MIC'ROSCOPE AND VIEWING DEVICE 10 Sheets-Sheet4 Filed Aug. 27, 1946 INVENTOR EDWIN c. wElsKoPF ATTO R N EY July 26,1949. E. c. wElsKoPF PROJECTING MICROSCOPE AND VIEWING DEVICE 1osheets-sheet 5 Filed Aug. 27, 1946 INVENTOR EDWIN C. WESKOPF BY lATTORNEY July 26, 1949 E. c. wElsKoPF 2,477,396

PROJECTING MICROSCOPE AND VIEWING DEVICE Filed Aug. 27, 1946 l0Sheets-Sheet 6 A vll 6 362, :no l aso I 368 r 3 2 E [2 Y INVENTovR EDWINC. WEISKOPF ATTORNEY July 26, 194:9. E Q WE|SKQPF 2,477,396

PROJECTING MICROSCOPE AND VIEWI'NG DEVICE Filed Aug. 27, 1946l l0Sheets-Sheet 7 "num INVENTOR EDWIN c. wslsnopf BY NM1 E. C. WEISKOPFPROJECTING MICROSCOPE AND VIEWING DEVICE July 26, 1949.

Filed Aug. 27, 1946 10 Sheets-Sheet 8 R O T N E V m ATTORNEY v July 26,1949. E. c. wl-:lsKoPF PRJECTING MICROSCOPE AND VIEWING DEVICE FiledAug. 27, 1946 lO Sheets-Sheet 9 INVENTOR EDWIN C. WEISKOPF 34A 164A I? fATTORNEY July 26, 194.9. E..c. wElsKoPF 2,477,396

PROJECTING MICROSCOPE AND VIEWING DEVICE Filed Aug. 27, 1946 y l0Sheets-Shea?l l0 aaa seo U Hh,I 3

as ses l a 2 INVENTOR EDWIN C. WEISKOPF BY i ATTORNEY Patented July 26,1949 UNITED STATES ATENT OFFICE Edwin C. Weiskopf, New York, N. Y.ppiication August 27, 1946, Serial No. 693,292

(Cl. Sil- 24) 13 Claims. 1

This invention relates to projectors for microscopes and othermagnifying devices, and this application is a continuation in part of myapplication Serial No. 515,735 led December 27, 1943 and my applicationSerial No. 597,286 led June 2, 1945, which have matured into Patent Nos.2,435,299 and 2,435,300, respectively, each dated February 3, 1948.

The apparatus to which the present invention relates is especiallyuseful by pathologists, other members of the medical profession,bacteriologists, pathologists technicians, and others, in themicroscopic examination of tissue or other specimens. The apparatusembodying my invention enables microscope slides to be projected througha conventional microscope in such manner that the image of the slidemagnied by the microscope can be viewed simultaneously by a group ofindividuals in any suitable projection room, with excellent reproductionof the slide on the screen, `or the image of the slide magnied by themicroscope can be projected into a viewing chamber as shown, forexample, in my Patent No. 2,378,672 granted June 19, 1945.

The apparatus of the present invention as disclosed in this applicationis Well adapted for accomplishing all of the objects set forth in myabove mentioned applications, of which the present application is acontinuation in part, and in addition the apparatus of this applicationenables I' various 'other desirable results to be accompushed,

One of the objects of the invention embodied in the apparatus of theinstant application is to provide a projector unit and a viewing chamberunit which, while completely separable from each other in their unitaryforms, respectively, can be easily and conveniently connected to eachother operatively so that the projector unit can be used either alone ina projection room or in association with the vewing chamber `unit whenit is desired to use the latter.

A further object of the invention is the provision of an improved lightprojector for use in projecting the images of micro-slides.

A further object of the present invention is to provide an improvedpower unit which is used in conjunction with the projector unit.

Another object is to provide interchangeable light mounting units, foralternative use with 2 the lamp housing and associated parts of thelight projector unit.

A further object is the provision, in conjunction with the projector andpower units, of improved electrical distribution means ior improving thesafety factor of the apparatus in respect to reducing or substantiallyeliminating the danger of personal injury attending the use of highvoltage apparatus.

The above and other object-s, features and advantages of the presentinvention will be fully understood from the following descriptionconsidered in connection with the accompanying illustrative drawings Inthe drawings:

Fig. 1 is a perspective view of the apparatus, showing the viewingchamber unit, the projector unit, and the power unit;

Fig. 2 is a front View of the projector unit;

Fig. 3 is a front perspective view, on a larger scale, of part of theprojector unit;

Fig. 3A is a section, line 3 3 of Fig. 3;

Fig. 4 is a top plan view of the top of the stand or the projector unitand of the movable support or carrier for the microscope and othermagnifying devices, parts being omitted for the purpose of illustration,and parts being shown in section;

Fig. 5 is an end view of the upper part of the stand and of the movablecarrier, the latter being shown partly in section;

Fig. 6 is a, perspective View of the reflector chamber of the projectorunit;

Fig. 7 is a perspective View of a part of the viewing chamber unit;

Fig. 8 is a vertical sectional View of the reiiector chamber of theprojector unit;

Fig. 9 is a side View of the power unit, partly in section, the housingbeing removed but indicated yby dot and dash lines;

Fig. 10 is a sectional view on the line {Q -i9 of Fig. 9;

Fig. 11 is a sectional view on the line I l-H of Fig. 2;

Fig. 12 is a View on the line l2-I2 of Fig. 11;

Fig, 13 is a sectional view lon the line l3-l3 of Fig. 12;

Figs. 14 vand 15 are sectional .views on the lines M-ld and l5-I5,respectively, of Fig. 13;

Fig. 16 is a perspective View of a terminal 3 holder for one end of atubular lamp of the light projector;

Fig. 17 is a perspective of the light housing, parts being omitted forthe purpose of illustration, showing the hinged closure removed from thehousing;

Fig. 18 i-s a perspective of the light housing, the closure being in anopen position, showing a light source of another type and showing auX-iliary devices associated with the light source;

Fig. 19A is a circuit diagram of light of Fig. 18;

Fig. 19 is a front View of the light housing When the latter isprovided'with the light source and auxiliaries shown iii-Fig 18; j

Fig. 20 is a sectional view on the line Zc-Z oi Fig. 2, the housingclosure being in its closed position;

Fig. 2l is a View similar to/Fig. 20, the housing closure being in itsopen position;

Fig. 22 is a View taken from the righto Fig. 2o

Fig. 23 is a view similar to EigQZZbutshowing the position of the partswhen the housing closure is open; Y v

Fig. 24 is a `perspective vieW of the lens support shownfirrFig.111p:

Fig. 25 is a perspective View of connector plug. .A ,Referring nowatothe.: drawings in detail, the yapparatus to which the 'present inventionrelates comprises: a;` viewing. unitrilil; a 4projector unit l,

.and a .povverfunit .l 411'1Theiviewing unit l comnprises.iaviewingicharnber lhvvhich is preferably 'off the constructionfsho'vvniinmysU. S. Patent l o.

2,378,672, said chamber beingmounted on a table .,il. -fAs here.shownvthetopof table l8gof the viewing .unitis provided'.viithfagrecessi 2li to receive thereinrfapzntfofntl'ietop .22. of thestand or frame 'Y Eliot fthefprojec'tor funit 1112'.: :The table orstand 2c is provided with a hingedfdroplea extension 2e supported byhorizontally:swingable brackets Z'ifwhich maybe.. swung .underethe top22 when leai extension lZiis'down;Asy illustrated, the units 9, l2 andI4 are each-.providedwithWheels or casters sothatthey arerindividuallymobile and may be fmoved `easilyfrorngfplace 'to' place.

In accordance vvvithethe-present invention, the apparatus isconstructedand @arranged so that thef-projectcr-.unit l2 may beused either with or-withoutithe viewingunit; i; .-fWhen-used without ftheviewin'giunit.l1,=said proector unit i2 may bedisconnecteduiromfsaidmviewing unit. For this 'purpose previsioni.V is'-.madeior :releasablyconnecting the light-reflector chamber 26 oi theyprojector-unit to .the upper-lightitunnel 28 of the viewing .unitsf'yhereleasableconnecting means preferably comprises a-flexi-ble'.bellows Se which -is fastened at onee-end-thereofV toltunnel 28 andwhich is providedatitsotheriend with a coupling part32 ladaptedtofbefreleasably fastened to chamber 2S in light-sealingrelation.therewith,4 as shown in Figs- .1 and.. z YMore. specifically, ashereshown, chambertsis provided with alight out- -let openingrllatvvhichsaid-,chamber has vertical-groovesL .in- Whichithe' coupling 32 isremovably received. Said coupling member is provided -With upper andlower.lateral-projections 33 and iii! and grooves 36 are provided withrecesses i2 located near-but above thelower ends of said grooves ortheinsertion of projections or. lugs lie. v'vlfienl lugs 4c areattheilfevel.of-recesses liZ, lugs 68 of coupling member 32 areabove theupper ends of grooves 36,' so that by lowering coupling, 'the upperlugs.38 varedisposed insaid grooves Aand lugs @le 'are positioned. in saidgroovesbelow the recesses 42. lIn this positionof `.the coupling member32, the outer face thereof abuts 'the' flat'iace fl i) iatter beingremcvednreierably screen' reflector :opening datand thecameraishiltte ofthe rectangular frame M of opening 38 in lightsealing relationtherewith.

The reilector chamber 26 is provided with a light inlet opening d5 whichis preferably controlled by a shutter iii as described in myapplication, Ser. No. 515,736. A plane mirror or other suitable lightreflector d8 is positioned in chamber instead of in the tunnel 38 of theviewing chamber, as in my above mentioned patent and application, forreflecting the image from the microscope 'ii/I or other magnier E,through open ing 3e, either to the reflector 59 of the viewing chamber,whenfthe lattenisiconnectedto chain-m ber it, or to .a screenfina..,.projection room, When 'the viewing chamber is disconnected fromchain= her 25 of the projector unit l2. It will be under-1 stooclthatwhen the viewing chamber is not used, 'for example', in the case ofoperation of the proe jector unit i2 for room projection, the viewingchambeiunit lil may be' entirely separated from the projector unit i2and moved out of the path of light emanating from light-outlet opening3d.

Chamber 2S is also provided with a light-ouilet opening 5E which isnormally closed by a re inovableshutter plate 5.61..;.A ground glassanother focussing screengE-.isvalsoremovablylniounted in chamber2S.atopening52. Li t-re'fle'ctor e yis is provided formoving said.reflectortoeither Vsaid positions, as ClescribedA above-.men-

1l1hencted thatlwhen sitio' hQvvn dotted unes ,in nig. s, anastacia.5.4. andante/m56 .are reinove chili@A light or image, fvronnft'hemicroscope or otherl i'nagnirler`` may,y b tran tted .through opening..32. .for proiectiononto. .a screen inl alero i ectionroonf1.without,disconnecting the .bellows froinfchambergQr,otherwisedisconnecting the viewing chamber unit lll from theprojection llnlt V25'. f i, .v y

The above.A described ,constlu on pfQvdeS. .alsohighly-desirablewaynfiakine Aphotgraphs ci "ie.magnified.image.transmittedtd-chamber, 26

from the'microscone orcthermagllen photographic, plateior apameramounted.Onas'iinpw inev plat-.ema the nositionedatoutlet neiii'ne Se. ingroovs.; bellows .itbeine idisccnnectedr. at opening ,5,12-Y in. the,ercovesior' ,the screen the homere-plis are takenwith1the;phpt9glaplicp latelorcarnera, as the casemayghg-nicuriteii@heretical-3e, as underthese conditions the focussing operation is facilitated. .More.speccalmwheliithebhw screen 53 atonenneagf.- libe-Photographic ,plateat Opening-'3e isautcmaticall .1n ,iceiis,1wh,enre flecteiztehinted.iaitsiullelinepcsitioaie. e) When the .pieturepithe. image. is.to be taken on a pnetographic .plateathe -latte pmtected by.. aremovable,lightgobillii 131.2115 @Quilted at Y .-.atihfllght inletopening of chamber 25 is utilized for controlling the time of exposureof said photograph plate, as described in my above mentioned applicationSer. No. 515,736. On the other hand, when the exposure is to be made bya camera which may be mounted at opening S4, the shutter 46 is adjustedso as to remain open and the time of exposure is controlled by theshutter of said camera, as described in my said application, Ser. No.515,736. It will be understood of course that shutter is adjusted toremain open during projection into the viewing chamber or onto a screenin the projection room.

Chamber 28 is supported by bracket arms B which are carried by stand 24and project upwardly from the top 22 thereof. A light housing kt2 iscarried by stand 24 and as here shown is supported in position thereonbelow top 22 by brackets E4. Said top 22 is in the form of a flat plate.A light-outlet tube 66 is connected to the light-outlet opening 68 ofprojector housing 2Q and extends through an opening in plate 22 to apoint thereabove as shown in Fig. 2, the open upper end of said tube 65being in registry with the inlet opening of chamber 26 through which thelight passes to reiiector 48. As will be subsequently described,provision is made for positioning either the microscope M or themagnifier E in registry with tube 66 over the open upper end thereof forprojecting a magnied image of the slide to the reflector 48. The upperend of tube G6 is provided with a plurality of vertically spaced shelves1|) for supporting one or more color lters which may be used inprojecting slides of certain tissue sections which are stained incertain colors.

An important feature of the present invention justing the position ofthe source of light in the projector housing. In order to provide asource of light of high intensity, there is utilized in the lightprojector of the present invention a high voltage mercury vapor tubularlamp 72. Said lamp 'I2 is preferably of the type which comprises aquarta capillary tube 14 provided with spaced electrodes at its oppositeends, pools of mercury adjacent said electrodes, and a discharge gas,such as argon. Lamp 12 is water cooled and for that purpose there isprovided a water jacket tube l5 of clear glass or other suitabletransparent material. Water jacket tube 76 is provided with aconstricted portion 78 which extends longitudinally of capillary tube 14in the portion thereof from which the light is transmitted to themicroscope or other magnifying device for illumination of the slide forforming the image. The purpose of providing water jacket tube 16 withsaid constricted portion 78 is to cause anincrease of the velocity ofthe cooling water around said light emitting part of lamp tube 14,whereby to avoid the formation of air bubbles which would impair theproper light emission characteristics of the lamp. The opposite ends oflamp tube 'I4 are provided with conductor terminals 80 which are inmechanical and electrical engagement with the companion conductingmembers and supports 62 and 84, respectively. More particularly, memberS4 is formed of metal and is provided with :a split sleeve Se in whichone end of lamp tube 'i4 has a removable sliding fit. Said member 46 ismounted in a metal block 88 which has an opening or bore ettherethrough. Block 88 has an integral annular ledge 92 which forms anabutment for the disk e4 which is nxed to the centering pin 96 integralwith sleeve 86 of member 84, said disk 94 being provided with aplurality of openings 98 to allow the passage of water into the waterjacket tube 16 at one end thereof. Disk 94 is held against abutment Q2by a spring le@ which is fixed at one end thereof in the tube |52 andwhich bears at its other end against said disk. Sleeve 36 is providedwith a cross pin |124 which fits in recesses |55 provided in member 50(Fig. l5) for preventing turning of member 84. The inner end of watertube |52 is provided with a flange |58 which is pressed against a rubberwasher or packing I I0 by a rotary sleeve or gland ||2 to form a watertight joint, between tube |02 and member 88 in the bore Sie thereof. Thelamp holding member 82 comprises a metal spindle ||4 having a cupped endportion i i6 in which the adjacent end of the lamp tube le is engagedand thereby supported. Spindle i4 is slidable in a metal guide H8 fixedin the metal tube |29. A spring |22 bears against one end of guide HSBand against the end HS 'of holding member 82. Tube |20 is mounted in anopening |122 in a holder member 24 formed of insulation material. Rubberwashers or packings |25 and |23 are mounted in members S8 and |24,respectively, for engaging the opposite ends of water jacket tube 'IB toprovide water tight joints between the opposite ends of said tube andsaid members t5 and |24.

Members 88 and |24 are removably supported on a pair of metal rods 35which project through openings in said members as illustrated in Fig.13. Each rod i3d is threaded at its opposite ends and is secured tomember S8 by nuts |32 which engage companion insulation sleeves orbushings |34 slidabiy mounted in the adjacent end of rod |35. Member |26is adjustable longitudinally of rods |35 and for this purpose the endsof said rods are engaged by nuts |36 which abut the companion insulationsleeves or bushings |33 which are slidably mounted on the ends of thecompanion rods. It will be understood that by tightening nuts |36against the companion bushings i 38 water jacket tube 'i5 is clamped atone end thereof against Washer 525 and at its opposite end againstwasher |252. The construction thus described facilitates the assembly ofthe lamp unit and provide convenient means for replacing the lamp 'i2when required. The terminal members t2 and 84 are connected to a sourceof high voltage by an insulated cable i4@ having insulated Wires |42 and|44 which are electrically connected to said terminals, respectively.

The lamp holder comprising members 88 and |24 and the above describedparts associated therewith is adjustably supported in the housing by theadjustable supporting member or bracket |56 which includes a bar |52having an integral lateral projecting portion |54 to which a plate |56is fastened in any suitable way as by screws |58. Member 38 of the lampholder is fastened to plate |5 in any suitable way as by screws |60. Thesupport |53 for the lamp holder is carried by the front pivoted closureor door |52 of housing 62, said door being hinged at the bottom thereofto the housing by-hinges |64 which removably engage the hinge pins |65of the housing G2. Support 55 has a downwardly and forwardly inclinedextension |55 (Fig. ll) which is connected to the lower part of the doorin the manner hereinafter described, bar |52 being connected to the doorat a point above the lower part of the latter by the mechanismhereinafter described, the construction and arrangement bewith thedifferent objectives, respectively, of the microscope. These sub-stagecondensers are not required and preferably are not used when the lightprojector of the present invention is employed. It will be noted lens226 is movable axially through a distance of such length that said lenshas a considerable range of adjustment to a plurality of positions alongthe length of the beam corresponding to the diameters or magnifyingpowers of the plurality of objective lenses respectively, of themicroscope. In saiddiiierent positions lens 226 is effective to controlthe width of the light beam in accordance with the diam-- eters of saidobjective lenses, respectively, whereu by to provide optimumtransmission oi light to the objective lenses.

It will be understood that the part oi' lamp 12 coextensive with therestricted portion 'i3 of tube 16 is positioned in centered relation tolens 226 for obtaining optimum transmission of light to said lens andthrough the latter to the ob-.

jectives of the microscope or other magnifying devices. This positioningof the lamp is accomplished by adjustment of the lamp holder support |58in a direction longitudinally of the lamptube axis, by operation ofshaft |12, and in a direction transversely of said axis by operation ofknob 222. It will be understood that for proper projection of the imagethe light beam from lamp 12 should be directed properly through lighttube 86 along a line in registry with the optical axis of the microscopeand that as much light as possible should be transmitted from said lampto the microscope. The means for the adjustment of lens 226 and themeans for adjustment of said lamp are therefore valuable features of theprojector unit I2.

The water jacket 16 of the lamp 12 communicates with the tubes |82 and|28, as above described, and the latter are connected to flexible tubes268 and 262. Tube 268 is connected to the outlet of a water i'ilter 264carried by closure |86 (Fig- 17). Tube 262 is connected to a nipple 266,mounted in closure |66 and the inlet of iilter 264 is connected to anipple 258 carried by said closure (Fig. 2). Said nipples 268 and 268project through the closure for connection thereto of the iiexible hosecr pipes 218 and 212, respectively, and the latter are connected to thewater supply in the power unit |11. The latter is provided with a rotarywater pump 214 and an air cooled water-cooling radiator 218. Pump 214 isoperated by an electric motor 218 and the radiator-cooling fan 280 isoperated by an electric motor 282. The outlet of pump 214 is connectedto flexible tube 218 by the pipe 211, the inlet or said pump beingconnected to the upper part of radiator 216 by pipe 219. The inlet atthe lower end of the radiator is connected to flexible tube 212 by thepipe 283 Thus, the cooling liquid for the lamp 12 circulates in a closedsystem, in the direction indicated by the arrows in Fig. 1., and is keptat a suiiiciently low temperature by said air cooled radiator 218 in themobile power unit |4. The cap for the iilling opening of the radiator isindicated at 285.

A step up transformer 284 (Fig. 9) is disposed in and constitutes partof mobile unit I4, the high voltage side of said transformer beingconnected to lamp 12. The preferred power of lamp 12 is i200 watts, saidlamp being energized at 1,000 volts and taking a current of about 1.4amperes. A flow-controlled switch (not shown) is associated with thewater-circulating system and preferably with the input side of thetransformer 284 for controlling the electric circuit so that in theevent of the failure of the circulation of cooling liquid through thejacket 16 of said lamp, the lamp is extinguished, preferably byinterrupting the primary of said transformer. Said flow-controlledswitch and various other auxiliary devices for controlling the electriccircuit of the lamp are also disposed in unit I I4.

Provision is made for eliminating or greatly reducing the vibration ofthe motor-pump unit 214, 218, of the motor-fan unit 280, 282, oftransformer 284, and oi all other parts which are of such character asto produce vibrations in the operation thereof. For this purpose all ofsaid units and parts are supported by a frame 286 which is mounted onrubber or other resilient blocks 23d carried by and secured to the baseframe 298 of tthe power unit I4. More specilically, as here shown, frame286 is preferably formed of angle iron and comprises lower longitudinalmembers 292 connected at their adjacent ends by lower cross members 294,upper longitudinal members 29S connected at their ends by upper crossmembers 298, and the upright members 38e, all of said frame membersbeing rigidly fastened together by welding or in any other suitable way.As the lower frame members 292 are anchored to the resilient blocks 288for supporting frame 288 and for securing it in position in the powerunit I4, said frame 285 being otherwise free from direct support by orengagement with the base frame 290 of said unit, any vibration of frame286 is largely absorbed by the resilient mounting blocks 288. Frame 286is in turn protected against substantial vibration by the provision ofrubber or other resilient mounting blocks 382 for the supporting frame304 for the pump-motor unit 214, 218 and for the motorfan unit 288, 282.As here shown, said frame 384 has a bottom 386 and sides 308, the latterbeing provided at their upper ends with lateral portions 3|@ which areanchored to the resilient mounting blocks 382 which in turn are fastenedto the upper longitudinal members 296 of frame 236. Thus, frame 384 issuspended from frame 288 by said resilient mounting blocks 382 so thatvibration oi the units carried by frame 304 is largely, if not entirely,absorbed by blocks 302 and thus prevented from being communicated toframe 286. The frame of the pump motor 218 and the frame of the ianmotor 282 are individually and separately secured to the bottom 305 offrame 304 at opposite sides, respectively, of said frame bottoni 885, asillustrated in Figs. 9 and 10.

Power unit I4 is provided with a housing cover S i 2 which is removablysecured to base frame 288 in any suitable way as by bolts or screws 3I4.Said housing is provided with an opening 3| for the inow of air to coolthe radiator 216. An opening SI1 is provided in said housing for theends of pipes 211 and 283. The top of said housing is provided with anopening 3I8 for access to the radiator filling opening 285 and with anopening 3I9, normally closed by a removable plate 828, for access toswitches mounted on the top of frame 286 as hereinafter` referred to.Said housing is open at its bottom so that it can be easily removed foraccess to the devices of the power unit. The interior of said housingSI2 of unit itl is lined with sound-absorptive material so as to reduceto a minimum the noise of the air dow induced by fan 288 as well as thenoise of the fan and of the motors in said unit. The reduction orsubstantial elimination of noise is a desirable feature of the presentinvention for obvious reasons and more especially because theY operationoi the-micro-projector may be accompanied by a lecture in respect to thesubject matter of the micro=slides exhibited in the operation of theprojector. This reduction or substantial elimination of noise is:effected to afconsiderable degree by the provision for AcausingV theradiatorcooling air to iiow into the housing of unit I 4 instead ofexpelling the air from therhousing past the radiator for coolingithelatter, especially since the noise of the air flowing into'the housingpast the radiator is-'largely absorbed by the sound absorptiv'e'materialof housing 312;

The electrical distribution means included in the apparatus of thepresent invention for operating theprojector lamp l2, the electricmotors and other electrically operated devices in the power' unit,` andother lamps and devices which are hereinafter referred to comprises'adistributionand control box' 3E4'whichis preferably provided as a partof the projector unit I 2 (Figs. l, 2, 1S and 19). Said distribution box324 is co veniently supported by lampV housing 62 by means of supportingrods 326. Current is supplied to distribution box 324 by the' detachableterminal plug 326 ofthe supply' line '333' which may be connected to anyconvenient-source of alternating current of ordinary'low voltage, say110 volts. A terminal 'connector block 332 (Figs. 18 and 19) is mountedin achamber 334 provided in box 324. Said terminali block is' providedwith a set of low voltage terminals 333 and a set or high voltageterminals 336; Box 324 is also provided with aplurality'oi low' voltageoutlet receptacles ses. A11 ofi sai-d low voitagejterminais or outletreceptacles 333 and 346 are connected in parallel to the inputreceptacle to which the low` voltage plug 326 is connected. A lowvoltage distribution line in the form of a iiexible insulated cord342 isconnected to the low voltage terminals336 of distribution box `524 andto corresponding low voltage terminalsv of a terminal block mounted inpower unit I4 for supplying' current to thev priu mary of transformer234 and to the' motors and other electrically operated devicesmountedvin said power unit. A high'volt'age distribution line in theform of a Yflexible' heavilyV insulated cable 344;:5 connected to thehigh voltage terminals 333 of distribution box 324 and to thecorresponding high voltage terminals o1 the terminal block which ismounted in the power unit for transmitting current at high voltage fromthe` secondary or transformer 264 to the terminals of light pro- .lectorlamp 12 to which the wires I4@ and E42 of flexible cable I44 areconnected as hereinbefore described.

The opposite ends of cord 342 and cable 344 are provided with quickdetachable plugs 346 and 348 engageable, respectively, with terminalblock 332 of the distribution box 324 and with the above mentionedsimilar terminal in the power unit I4. Said'plugs 346 and 346 are of thesame construction and as shown in Fig. 25, with reference to plug 346,each of said plugs comprises Van insulation block 350 having a dat face362 provided with prong low voltage terminals 334, which engage the lowvoltage socket terminals 336 of block 332, and high voltage socketterminals 356 which are engaged by the high voltage prong terminals 338of said block 332. 1t will be understood that cord 342 is connected atits opposite ends to prong terminals 354 of plug 346 and to the similarsocket terminals of plug 348, and similarly that cable 344 is connectedat its opposite ends to socket terminals 356 of plug 346 and to thesimilar socket terminals of plug 348. Plug 343 is releasably secured todistribution box 324 by suitable releasableV fastening means, here shownas a pair of clasp members 353 pivotally mounted on said box inpositions above and below chamber 334 (Figs. 18 and 19) for releasableholding engagement with catch members 360 (Figs. 2 and 25) provided onplug 356. Similar fastening means is provided on power unit I 4 for plug348.

It will be noted that power unit I4 is mechanim cally separate from theprojector unit except for the exible Water tubes 213 and 212 and theflexible electric conductor cord 342 and cable 344, so that the devicesin the power unit are maintained out of vibrating relation to theprojector unit I 2. By mounting the transformer 264, the motor o"-erated water pump and the motor operated fan for the radiator out ofvibrating relation to the stand 24 of the projector unit I2, thevibrations of said transformer and of the other electrical or movabledevices in unit I4 are prevented from being transmitted to themicroscope M or to the enlarger E on said stand. Accordingly themicoslides or other transparencies or objects the imm ages ofV which areprojected into the viewing chamber or onto a screen in the projectionroom, as the case may be, are protected against vibration so that suchimages are steady and distinct for observation, free from theundesirable elects which might otherwise result from the eiTects ofvibrations.

In View of the high voltage in the lamp housing 62 of theV projectorunit I2, safety means are pro vided to eliminate the danger of personalinjury which would be present in case access to the in-V terior of saidhousing could be obtained when high voltage is connected to theterminals of the lamp holder. For this purpose, provision is made forpreventing opening of closure I62 when plug 346 is connected to thedistribution box 324 and for preventing the connection of said plug tosaid distribution box unless the closure I62 is in its closed position.Referring in this connection to Figs. 11, 18, and 20 to 23, itr will beobserved that a rod 362 is slidably mounted in aligned openings 364 and366 of lamp housing 62 and chamber 334, respectively. Said rod 362 isprovided with an operating member 363 which also constitutes stop meansengageable with housing 62 and box 324 to limit the movement of said rodin either direction. An interlock member 363 is rigidly secured toclosure I62 at the inner side thereof and is provided with a lateralextension 316 which overlaps the companion interlock member or rod 362longitudinally of the latter (Fig. 20) when said rod is in one positionthereof and closure i 62 is closed whereby the latter cannot be openedwhen said rod projects into housing 62. On the other hand, unless rod362 is in the position in which it projects into housing 62 and isdisposed in the path of extension 310 of interlock member 368 so as toprevent opening of closure I6?, plug 346 cannot be inserted into thereceptacle chamber 334 of the distribution boX 324 for connection withthe terminals 336 and 338 of terminal block 332. Thus, as shown in Fig.21, when the closure I62 is open, rod 362 projects into receptaclechamber 332 and thereby prevents insertion of plug 346 into said chamberand thereby prevents the connection of the terminals of said plug withthe terminals in said chamber. In order to prevent plug 346 from beinginserted in chamber 334 and connected to the terminals therein unlessthe closure |62 is closed provision is made for preventing retraction ofrod 362 from said chamber, and for this a barrier member 312 is arrangedto close opening 354 when closure |62 is open, as shown in Figs. 21 and23. Barrier member 312 is secured to the housing side Wall which isprovided with opening 364 for rod 352 and is mounted for pivotalmovement in any suit= able way as by a pivot screw 314 for movement froma projected position in which member 312 covers said opening (Figs. 21and 23) to a retracted position in which said opening is uncovered(Figs. 20 and 22). A tension spring 315 is connected at one end thereofto member 312 and at its opposite end to the wall oi housing 52 formoving member 312 to its projected position, under the control ofclosure 162. A stop pin 315 is mounted on the Wall of housing 62 toengage and position barrier member 312 in said projected position of thelatter. Said barrier member is provided with a laterally projectingrabutment 383 which is engaged by interlock member 352 for movingbarrier 312 to its retracted position when the closure lEiZ is closed.Thus member 312 is movable into and out of the path of intern lockmember 362 under the control of closure |62 so that plug 346 cannot beinadvertently inserted in receptacle chamber 332 for energizing theterminals of lamp 12 unless said closure is in its closed position sothat access to the interior of the housing is thereby prevented.

It will be observed that the power unit lli is automaticallyrie-energized electricallv when plug 245 is disconnected fromdistribution. box since the supply of electricity to the electrical instrumentalities of said unit is transmitted tliere= to only by line 342which is automatically elec trically disconnected from the source ofcurrent by disconnecting plug 3de. Moreover, there are no live terminalson plug 355 when the latter is disconnected and there are no liveterminals on plug 353 when plug 345 is disconnected, and fur thermore ifplug 343 is disconnected While plug 365 is connected the only liveterminals of plug ses are the low voltage terminals thereof. Theprovision on the same plug 34S of both the low and the high voltageterminals eliminates the danger of exposure to high voltage at therecepH tacle chamber 33e when said plug is reinored therefrom.

is indicated above, the projector unit i12 includes means ior mountingand positioning either a microscope M or another optical magn niiier orenlarger E selectively in registry with the upper end of light tube SE.The means pro vided for this purpose comprises a carrier 382 (Figs. l towhich is slidably mounted on the top 22 of the projector stand 2:55 andwhich carries the microscope M and the magnifier E. Said carrier 332comprises a plate 383 provided with depending brackets 384 each providedwith a roller 39S which rides on a companion. guide rail or rod 38Scarried by the top 22. Said rails are disposed in laterally spacedrelation and as clearly shown in Fig. l one of said rails is spacedlongitudinally of the other two rails to conform to the similararrangement of the companion roll ers respectively, 0f carrier 332. Saidrails are secured in companion pairs of longitudinally spaced supportingmembers 325 which are fas1 tened to the top or stationary supportingplate 22 in any suitable Way, as by screws 392. Adjustable stop rods 394and 355 are provided on carrier 332 in position to engage the adjacentbracket arms iii), respectively, when the microscope M or the magnier Eis in registry with light tube B6, as the case may be. As shown in Fig.4, stop rod 394 enages one of the arms 52 when the carrier is positionedso that the optical system of microscope is in registry with light tubeSi), as shown in Fig. 2, and it will be understood that stop rod 326engages the other bracket arm 6G when the magniiier E is positioned inregistry with said light tube. Adjustable clamps 393 for rods 39e andSSS are secured to plate 3&3 of carrier 382. Said plate 383 is providedwith an opening 40G (Fig. Ll) to permit movement of carrier 382transversely of light tube Sii. Said carrier is provided with a handle4132 as conu venient means for moving said carrier longitudinally ofplate 22.

The carrier plate 383 is provided with adjustable means for releasablyholding the microscope in position on said plate. As here shown (Fig.e), said adjustable means comprises a block @dei and blocks 406engageable with the ends of the forked base of the microscope. Saidblocks are slidable on plate 383 and are provided with longitudinalslots 423 in which the stems of companion adjustable clamping and guidescrews im are disposed, said screws being into plate 333. Additionalreleasable clamping means M2 are provided, as shown in Fig. 3, forreleasably engaging the forked ends of the miE croscope base at theupper surfaces thereof to hold the microscope firmly on carrier plate383.

The enlarging device E comprises magniers Mi and M2 mounted on a post H4carried by a frame 4|S fastened to the top of slide-ble carrier plateThe top li'i or said frame is provided with a light opening 42d whichregisters with the light tube @E when the enlarging device E is in itsoperative position. it will be understood that each of the magnifyingdevices Mi and M2 includes a set or lenses for obtaining the desiredmagnications of the slides of these magniers, respectively. Magniers Mland M2 are turnn able about the axis or post iii/l for registering saidmagnifier selectively with opening Magnifying devices Mi and M2 areadjustable vertically toward and away from light opening [320 in anysuitable way as by a conventional pinion and rack device operable by arotary 22. Frame tll is releasably secured on the top of carrier platein any suitable way as by screws 42d which pass through the base flange426 of said frame and are threaded into open-z ings in said plate 333. Alens 428 may be mount'- ed in the grooves at the upper part ci lighttube Bil, instead of the filter which may be used, indicated above,`when the microscope is used, said lens serving to provide a wider beamoi' ligh' for the magniers Mi or M2 when the latter ar used, since thelens of magnifers Mi and M2 ar of larger diameter than the microscopelenses. It will be understood that when the microscope is used lens 225in the housing G2 is adjusted to condense and concentrate a maximumamount of light on the objective lens of the microscope throughout the.area of said objective lens. On the other hand, when the magnifier E isused, the lenses of the magnifying devices Ill/ii or being larger thanthe microscope lenses, require for best performance a wider beam oflight than the comparatively narrow beam directed onto the microscopeobjective lens. rlhe provision of this Wider light beam is accomplished,as stated above, by the use of an auxiliary lens such as the lens 42 3.

The provision in the apparatus of the present invention for positioningeither the microscope Mandoneor moreotherfmagniiiers, such as'theVmagniiers'Mi and M2, is highly desirable as it enablesdilerentlymagniiied to be pron jected selectively vby the light projector of thepresent invention, for example, a slide or photo-- graphic transparencyor a cancerous growth c beV projected lthrough the magniiiers Mi orfollowedby the proj ection=through the micros M of a microslide carryinga microscopic s ion ofsaid cancerous growth, thus enabling observationand examination ci the microscopic section ofvarious areas thereof incomparison with an enlargement of the cancerous growth from which saidmicroscopic section was obtained. ,Further it will be understood that byadjusting the frame Fzforvarying the magnifying power ofthe micro scope,various areas'oithe microscopic section c.. ried by the microslide inthemicroscope can be selectively magnified as may be required examinationof Vsaid section.

When it is desired to take colored photogr of the-slide or othertransparency or other @blc-t magnified-by the microscope M or by theenlarger E, as the case may be, an incandescent lamp .c utilized in thehousing of the light actor, i

for

stead of the lamp l2. Accordingly, provis.v 3 made for substituting acomplete lamp-moi g and adjusting unit 'carrying the incandescent lampas a part of the unit in place o1 ing and adjusting unit which carriesis illustrated Figs. -18 and 19 where it 1 cated by the referencenumeral il fi comprises a hinged closure or panel i with-hingemembers'lilA for engagement x the hinge pins 1651er the lamp housing t2 w thehinged closure `or panel It?, provided mountingV means vfor the tubularlamp is emoved. In other words, it will be understood that whenthe'incandescent lamp is to 'ne used closure 152, together 'with all ofth ried thereby, is removed from the hou the hinged closureV 162A offtheunit is connected to said lam-p housing. The lamp 32 of unit 43@ ismounted on a bracket c3@ which is fixed to and carried by the slidabieholder lQA which corresponds to the bracket or holder iidof the otherunit. Bracket which carries lamp 32 is moved forwardly and rearwardly bya mechanism which is the saine as the mechanism provided in the otherunit for moving the tubular lamp l2 forwardly and rearwardly, and saidbracket 434 is movable longitudinally of the lamp housing by a mechanismwhich is. similar to the mechanism provided in the unit for movingtubular lamp l2 longitudinally ci its axis. The iirst mentionedmechanism by which the lamp carried by the bracket itil is movedforwardly and rearwardly comprises the parts shown in Figs. 1l and 13'and are designated by the same numerals, respectively, with the letterA added. The mechanism for moving the bracket f hen toll and the lampcarried thereby longitudinally or the lamp housing comprises the rotarysha-it itin which is operable in the same way as the shaft i'ii, saidshaft having a screw-threaded portion liln which is in threadedengagement with a member 435 Xed to bracket 43d, so that by rotatingsaid shaft IlEA said bracket is movable longitudinally of said shaft.Thus, lamp i332 is mounted for movement substantially in a horizontalplane in two directions at right angles to each other for registeringsaid lamp with the light outlet S3 of the lamp housing.

Unit 43E) 'also carries a step-down Vtransformer 11,6., 438, anadjustable rheostat Mil 'provide rotary ad/justingrknobzficf, Ia voltKmeter switch 4435. Said unit' is also .pro-vidopening M8 lfor theelectricsupply co; has a terminalfplug G52 which isdeta hably gageablewith theterminals ci one ci receptacles 340V of. distribution boi; i525.observedthat lamp 4t2. operates at a low vol the normal Voltage ratingci said. lamp vb about 6 Volts-and the normal power rating l 60 watts;Transformer i3d is operable the normal 110 voltage of the outlet reSilit vto a Voltage which is -a liew Volts higl the normal voltageratingoi lamp in stat Mil which in seriesy with the tran-si primary(Fig. 19A)v is. eiectivc to control voltage-at lwhich ther-lamp isoperated. More ticularly, in operating the `light proies* the lamp @32,lrheostat te@ is adjusted the Vapplied voltage'the lamptakes more trnormal current rating of V'the lamp so that s lamp burnskmorebrilliantly than would be case it operated at its normal voltageand c rent rating. The'meteril is" utilized for 'indicating `the voltageat which the lamp operai su'ant "to the adjustment 'of rheostat d withabove is an over eXcitedor yover energized tion of the lamp whichresults in the brilli the illumination provided by said lam'over-excitation oi the'lamp needbe prov momentarily `at the time ofexposure in t. photograph, the `liieof the llamp is not shortened.

Provision is Amade in accordance with the present invention for coolingthe microscope lenses and the micro-slide while the latter is positionedon the stage S of the microscope. in connection,`V it will be understoodthat the intense light which omanates from the high voltage lamp 'l2which is the vlamp utilized in the lamp housing of the projector unitfor producing -magnied images of the micro-slide by means of themicroscope M lis accompanied by intense heat which may impair themicro-slide and the objective lenses of the microscope through whichsaid beam of light is projected. These undesirable results areeliminated by the cooling means embodied in the projector unit l2. Ashere shown (Figs. 2 and 3) ,said cooling means comprises a motoroperated vfan #its which is mounted in a frame 455 carried by stand 2&3adjacent bracket arms Eil. It will be noted that fan t5@ is positionedin relation to light tube 5ft so that when carrier 332 is moved toposition the microscope M, with the optical axis of the microscope inregistry with said light tube, as shown in Fig. 2, a stream of coolingfair is directed by fan 4541 for cooling the micro-slide which ispositioned on the stage S of the microscope for counteractihg theheating eiect of the light beam on said slide and on the microscopelenses. Similarly it will be noted that when the magnier E is inoperative position, as illustrated in Fig. 3, fan 454 is eiective todirect the stream ci cooling air on the slide or other transparencywhich may be positioned on the top llt of frame dit for projectionthrough the magnifier M--l or M-2, as the case may be. The electricmotor which operates fan 454 may be connected by a suitable cord (notshown) to one of the outlet receptacles 346.

When the Vhigh voltage lamp i2 lis used, which y is usually the case,unit 430 being removed and the lamp mounting unit or closu-re |62 beingmounted on the housing 62, the power unit I4 is likewise used. It isconvenient to provide manually operated control switches on the frame286 of said power unit for starting and stopping the operati-on o-f :themotors 218 and 252 and for connecting and disconnecting the primary ofthe transformer 284 to and from the source of electricity. For thispurpose a switch panel 450 is mounted on the top of frame 28B (Fig. 9),said panel Ibeing provided with said switches which are accessiblethrough opening 3 I9 of housing 3l2 when closure plate 320 is removed.

' It will be understood that the invention may be embodied otherwisethan as herein specifically illustrated or described and that in theillustrated embodiment and certain changes in the details ofconstruction and in the arrangement of parts may be made withoutdeparting from the underlying idea or principles of the invention withinthe scope of the appended claims. Having thus described my invention,what I claim and desire to obtain by Letters Patent, is:

1. In micro-projection apparatus, a light projector unit and a viewingchamber unit mounted on their own relatively movable supports 'which areindependent of each other; said projector unit comprising a lighthousing, a support for a microscope, and light receiving and reflectingmeans disposed above said support so that light which is transmittedfrom said housing through the optical system of the microscope, when thelatter is positioned on said support, is received by saidlight-reflecting means for reflection by the latter; and means forreleasably connecting said viewing chamber to said projector unit inlightreceiving relation to said reflecting means for transmission by thelatter of micro-images into said' viewing chamber, said independentsupports and said releasable connection enabling separation of saidunits so that said projector unit may be used for the projection ofmicro-images onto a screen independently of said viewing chamber.

2. In micro-projection apparatus for use with a microscope, alight-projector unit which includes a horizontal support for amicroscope, a light housing having a light outlet for the passage oflight from said housing through the optical system of the microscope,and a light-receiving chamber in said unit disposed above saidhorizontal support in light receiving relation to said light outlet inposition in said unit so that the light which passes from said housingand through the microscope is received in said chamber, said chamberhaving a light-outlet; a viewing chamber having a horizontallight-receiving surface therein, a light passage having means fordirecting light to said surface, and provided with a plurality ofviewing openings for observation of said surface from points externallyof the chamber; and means for removably connecting said light passage ofthe viewing chamber to said light outlet of said light-receiving chamberof said projector Iunit for the transmission of light from the latterand through said light passage to said surface or" the viewing chamber.

3. A micro-projector unit for use with a microscope, said unitcomprising a stand providing a support for the microscope for mountingthe latter in position to receive light from a light projector, andmeans carried by said stand in position to receive the light whichpasses through the optical system of the microscope, when the latter ispositioned on the stand, and to project lil.)

the light onto a screen, said last mentioned means comprising a chamberhaving a light inlet, two light outlets in spaced parallel planes atright angles to the plane of said light inlet, and a rellector movablymounted in said chamber between said light outlets in the path of lightwhich enters said chamber through said light inlet, said reflector beingmovable to two different positions to reflect the light to said twolight outlets, respectively.

4. A micro-projector unit for use with a microscope, said unitcomprising a stand providing a support for the microscope for mountingthe latter in position to receive light from a light projector, andmeans carried by said stand in position to receive the light whichpasses through the optical system of the microscope, when the latter ispositioned on the stand, and to project the light onto a screen, saidlast mentioned means comprising a chamber having a light inlet, twolight outlets in spaced parallel planes at right angles to the plane ofsaid light inlet, and a reflector movably mounted in said chamberbetween said light outlets in the path of light which enters saidchamber through said light inlet, said reflector being movable to twodifferent Ypositions to reilectthe light to said two light outlets,respectively, means on said chamber for mounting a translucent screen atone of said light outlets, and means on said chamber for mounting aphotographic plate at the other of said. outlets.

5. A micro-projector unit for use with a microscope, said unitcomprising a stand providing a support for the microscope for mountingthe latter in position to receive light from a light projector, andmeans carried by said stand in position to receive the light whichpasses through the optical system of the microscope, when the latter ispositioned on the stand, and to project the light onto a screen, saidlast mentioned means comprising a chamber having a light inlet, twolight outlets in spaced parallel planes at right angles to the plane ofsaid light inlet, and a reflector movably mounted in said chamberbetween said light outlets in the path of light which enters saidchamber through said light inlet, said reflector being movable to twodifferent positions to reflect the light to said two light outlets,respectively, means on said chamber for mounting a translucent screen atone of said light outlets, and means on said chamber for mounting aphotographic plate at the other of said outlets, and a camera shuttercarried by said chamber at said light inlet for controlling the exposureof the photographic plate.

6. In micro-projection apparatus, a projector unit comprising a lighthousing vfor an electric lamp operable at a high voltage, and electricaldistribution means comprising a panel box having a set of low voltageterminals and a set of high voltage terminals therein, said high voltageterminals being connected to said lamp, means for connecting said lowvoltage terminals to the primary of a step-up transformer, meansremovably engageable with said high voltage terminals for connecting thelatter to the secondary of the transformer, said two last mentionedconnecting means comprising a unitary connecting member carrying low andhigh voltage terminals removably engageable with said low and highvoltage terminals, respectively, of said distribution means whereby saidtransformer is automatically deenergized when said terminals of theunitary connetting. ,memberare remorediromsaid terminals forthelpanelbox.

7. lInl micro-projectionjuapparatus comprising a proj ectorunit having alight housing provided with, electric lightthereln; a. power .unitseparate frQIrL but Vassociated withsaid projector, said "powerunitincluding a step-up transformer for supplying current at an e1 evated voltageto .said iight; electric distributionj means carried .bysaid projector, 'said distribution means including a set ofrlowvoltageterminals adapted to be conjnected to a source of. low voltageanda set of high voltage terminals connected tothe Vterminals ofz .saidlight; electrical connecting means L between said low voltagejterminalsand the primary/of said transformer, and electrical oon- ;jnecting meansbetween the secondary .,Of v said [transformer and said vhigh voltageVterminals, said two'iast mentioned connecting means comprising a'vunitary connecting member' carrying 10W and V"high voltage terminalsremovably engageable with said lowA andhigh voltage terminals,respectively, vof said` distribution means whereby said transformer isautomatically de -energized when said v terminalsof the unitaryconnecting member .are removed from said terminalsof the panel box.

'Y 8; In micro-projection apparatus, a projector unit comprising a lighthousing for Van electric lamp operable at a high voltage, and electricalY distribution means comprising a panel box having a set of low voltageterminals and a set ,of high voltage terminals therein, said high voltage terminals being connected tosaid lamp, means for connecting said10W voltage terminals to the pri- 'mary `of a step-up transformer, meansremovably n engageable with said high voltage terminals for connectingthe latter tothe secondary of the transformer, said two last mentionedconnecting lmeans comprising a unitary connecting member carrying `lowandl high voltage terminals remov- -rably engageable with said low andhigh voltage VLterminals,respectively, of said distribution means."Whereby said transformer `is'"au tomati'cally de- -1-energized whensaid terminals -of the unitary con- ..-nec'ting member are removed fromsaid terminals `of the panel box, a=closureforsaid housing ymov- .ablefrom a closed position'to an-.open position, i and means-for.preventing-4 movementof said y.aclosuretosaidopen position Whensaidhigh volt- -.age..terminals are .connected to the transformer andlforpreventing .theconnection of said high #voltage terminals to .thetransformer-by said removable means when saidzclosure is in. said open i.position thereof.

1. 9; vIn micro-proj ection apparatus comprising. a

with electric light therein; apower-unit.separate Yfrom b ut associatedwith s aidaprojectorVsaid :power unit includinga. step-uptransformer for.supplyingcurrent at an ,elevatedvoltage to said,

a terminals Vconnected to the terminalsof said light@ .felectrical.connecting means .between said low voltage terminalsandthe primary ofsaid trans- -mformen and electrical connectinggmeans. betweenigxthesecondary ofsaidtransformer and said high .voltageterminals,.a,closure for saidhousingmov- `ablefroma .closedposition toan openposition, andA means for preventingv movement of said :=.closureto said Aopenposition when said. highvolt- .fagegterminals Aareconnected to..;the,.transformer l anda-rior. preventing ,.theconnection.. onsaid high` voltagetermi'nals to the transformer,bv..,said removable member When saidclosurefis insaidopen positionthereof.

10. In alight projector. for a microscope,.said

y projector comprising a lamp, housing for .an electric lamp for thelight. projector, and a closurafor said .housing movable from aclosedpositionin which the closure bars access Vto the interiormf saidhousing, to anopen position forpermitting .accessto .theinterior of thehousing; releasable ,means for connecting saidlamp yelectricallyto asource of .electric current, means for vpreventing movementof saidclosure tosaid openposition thereof unless said connecting meansis.discon- .nected from said source, and meansforypreventing theconnectionof said lampto said source vunless said closure is in .itsclosedpositionsaid closure movement preventing meanscomprising an interlock membercarried by said closure at ,the inner side thereof, and a movableinterlock v.member in holding relation to said. rst. men

tioned interlock member in saidy housingwhen l said connecting' meansisoperative toconne'ct ...said lampto said source, said movable;interlock releasably operable under the .control of .said

closure for preventing movement of. said vmovable interlock member from-said. connectionpreventing position when. saidclosure is -open.

11. In microprojectionapparatus,.a,projector unit vcomprising alight-housing -foran electric f lamp operable at. avhigh..voltage,.,and-electrical distribution meanscomprising a panel .box.having a set of loW voltageterminals and. aset l cih-ign.voltageterminalstherein, saidhighvoltage ter- Yminalsibeing connected.to said. lamp, means .for

. connecting said low voltage lterminals-to.then-primary of a ystep-.uptransformer, means removably engageable with saidhgh voltageterminals.,or

connecting the latter to the secondary 0f ,the transformer, a closurefor said .honsihngfmovable from a closed position, in which theV.closure bars accessto the interiorvof saidhousing, to anropen positionfor permitting accesstothe interior of the housing, .and Vmeansincluding a member mov- ...ablein said panel box and insaid housing-for`preventing movement of said closure to said open l position thereofWhen said. terminals -ofthefpanel 1 `box areconnected tothe transformerby saidcon- '5 -.proJector Vunit having a light yhousingprovlded 5nectingmeans and for preventing connectionfof said terminals to saidtransformer by said vconnecting .means when said closure is in said.open

. .position thereof.

12. .In .micro-projection apparatus. a liebt :pro-

; jector Vunit and a viewing chamberi unit mounted on their .ownv`relatively. movable .supports .which .are inclependenty of ,eachother; said projector unitcomprising a light housing, a support-for a...microscopia andflight receiving. and reiieting means-.disposed abovesaid supportso 'that light whichfis.transmittedfrom said housingthrough.the optical system of the microscope,v when; the

\ latter4 is positionedonsaid support, .is received by said lightreilecting means. for relectionby vthe ylatter; and meansV including .aA flexible bellows for ;releasab1y.conne cting said `viewing chamber :l

.to saidlprojector .unit inlight-receiving `relation

